Patent GB-601997-A (GB)
Title: Improvements in grinding machine
IPC: B24B5/06
Filed: 1945-06-21
Abstract: 601,997. Grinding-machines. WESSMAN, W. G. June 21, 1945, No. 15859. Convention date, June 21, 1944. [Class 60] In a grinding-machine in which both the work and the tool are rotated and in which they have relative traverse, short, rapid reciprocations are superimposed on the traverse. In Fig. 1, the tool 199 is rotated through belting 204 by a motor 203 and is mounted for rapid reciprocation, through belting 224, 275 and an adjustable crank 229, by a motor 216. The crank is connected with a slide 172 swivelmounted on a flange 166 carried by a member 154 adjustably slidable on a carriage 145. The flange 166 has arcuate adjustment slots for the bolts securing it to the member 154, and these bolts co-operate with stop lugs to limit the swivel movement of the slide 172, the assemblage being lockable against swivelling by a nut 178 operated by a handle 179 which draws a tapered central bearing pin 171 into a correspondingly tapered socket. The carriage 145 is slidable in dovetail guides 144 by a hand wheel 158 on a screwed feed-shaft, the wheel being associated with an adjustable graduated index ring. The work 123 is held in a chuck 122 manipulated by a hand wheel 125 and driven through change-speed belting by a motor 118. The work-head 47 is swivel mounted on a slide 71 which is movable for traversing, against spring opposition, relatively to the tool 199 by a lever 95, the movements of the slide being limited by adjustable stops 89, 92. The slide 71 is swivel-mounted on a table 13 longitudinally slidable on the bed 11 by a hand wheel 31 through wheel and rack gearing. The movement of the table 13 is limited by adjustable stops 27, 28 and the table may be clamped in any position of adjustment by a screwmember 46 which closes a split sleeve embracing a guide rod. The swivel bearings comprise tapered central bearing pins and correspondingly tapered sockets, and locking is effected by tightening screws 66 which force, radially inwards, rods having bevelled ends which engage a counter-tapered recess in each tapered pin, the consequent cam-action forcing the pin into its tapered socket. The swivel mountings of the work and tool heads, permit the tool to be reciprocated in a path parallel to the direction of traverse of the work; irrespective of the angular setting of the work holder, e.g. when the work-piece 328, Fig. 2A, is ground internally, the work is traversed parallel to the path of the table 13, and the tool 331 is corresponding reciprocated during the grinding of the surfaces 329, 329a, and the traverse and reciprocation is along lines 335, 336 when the bevel end 334 of the tool is operating on the surface 330. The rate of rotation of the work is related to the rapidity of reciprocation of the tool, e.g. with a one-half inch wheel, grinding a fiveeighths inch hole, rotating at about 50,000 r.p.m., the work should turn from 43 per cent to 143 per cent, and preferably 93 per cent of a revolution for each reciprocation. In another example, a stroke of .0625 inches and 390 to 575 revolutions per minute are mentioned. The finish deteriorates outside the limits mentioned. . In a modification for contour grinding, the motor, belting and crank 216, 224, 275, 229 are transferred to the work holder, an additional slide being interposed between the table 13 and the slide 71, the latter being turned through a right-angle from its position in Fig. 1. The lever 95 is used to maintain the slide 71, in opposition to spring means, against a stop 92, during the retraction of the work from the wheel by operation of the table 13, contact between the wheel and the work during retraction being thus prevented. The other end of the slide carries a cam-follower which contacts, under the pressure of the spring-means, with a cam-bar, shaped according to the contour to be ground. The cam is carried by a support which is adjustable on the bed of the machine. The slide 172 of the tool-holder is adjustable by a hand wheel on a screwed shaft, and is locked by clamping a split sleeve on a guide rod. Feed is put on, as before, by the wheel 158. In a modification for straight and multiangle grinding, but not for contour grinding, wherein the tool-holder is reciprocated, the apparatus is mountable upon a bench or pedestal. The table 13 of Fig. 1, being designed for the special bed 11, is therefore replaced by a lower slide similar to the slide 71 and similarly operated by a handle 95. The lower slide is swivel-mounted on a base-plate which is attachable to a bench and carries the tool mounting.